The present invention relates to a liquid crystal display, and more particularly to a liquid crystal display which enables the saving of power by adopting a novel signal transmission method by optimizing wiring constitution for supplying driving signals to driver ICs mounted in a flip-chip method.
A liquid crystal display of a STN (Super Twisted Nematic) method or a TFT (Thin Film Transistor) method has been popularly used as displays of notebook type personal computers and the like. Each liquid crystal display includes a liquid crystal display panel and driving circuits for driving the liquid crystal display panel.
Among such liquid crystal displays, there has been known a so-called flip-chip method (FCA) liquid crystal display which mounts silicon chips on a transparent insulation substrate forming a liquid crystal display panel as described in U.S. Pat. No. 5,739,887 (Japanese Laid-open Patent Publication 122806), for example. The silicon chips are provided with connection terminals (bumps) and are electrically connected with electrodes formed on the transparent insulation substrate. Further, the silicon chips are provided with driving circuits and these driving circuits input control signals, a power supply voltage and the like through the electrodes on the transparent insulation substrate and output signals for driving the liquid crystal display panel to the electrodes on the transparent insulation substrate.
Japanese Laid-open Patent Publication 13724/1994 proposes a liquid crystal display which uses wiring formed on a substrate of a liquid crystal display panel for mutual connection between silicon chips (a sequential serial supply method, a bucket relay method). (Hereinafter referred to as “data transfer method”).
As one of signals transmitted through wiring among silicon chips, display data is referred to. The display data is data for displaying images on the liquid crystal display panel and is transmitted to a driving circuit as digital signals. When the gray scale of the liquid crystal display are increased in number, the number of bits of the display data is also increased and the number of wiring is also increased. The wiring formed on the transparent insulation substrate have the wiring resistance and the parasitic capacitance so that when the display data is frequently changed, there arises a problem that the power consumption is increased. Further, recently, it has become no more possible to ignore the power consumption derived from the wiring in the inside of the silicon chips. Further, when the number of gray scales is increased and the number of wiring is also increased, the power consumption is increased correspondingly so that the problems becomes outstanding.